1. Field of the Invention
The present invention relates generally to a sheet processing device and an image forming system.
2. Description of the Related Art
Image forming apparatuses for producing printouts of digital information and folding devices connected to or mounted inside an image forming apparatus to fold a printout sheet(s) on which an image(s) is formed by the image forming apparatus have become necessary equipment in recent years.
When a sheet is folded by such a folding device, because a crease formed in the sheet is not crisp, the height of the folded sheet will be large. To alleviate this disadvantage, a folding device including an additional folding mechanism that presses a crease to reduce the height of a folded sheet is already proposed and known. Examples of such a folding device are known from Japanese Laid-open Patent Application No. 2007-045531 and Japanese Laid-open Patent Application No. 2009-149435.
However, position of a crease formed in a sheet is not always the same; rather, the position varies depending on a fold type and the size of the sheet. Accordingly, conventional folding devices have a disadvantage that a user is required to set (specify) an additional folding position each time when pressing a crease formed in a sheet so that the crease is pressed adequately. Thus, conventional folding devices disadvantageously cause inconvenience to users.
Therefore, there is a need for a technique for increasing user convenience at causing a crease formed in a sheet to be pressed.